U.S. patent application number 15/216739 was filed with the patent office on 2018-01-25 for recycling process for expanded polystyrene wastes.
The applicant listed for this patent is Nano and Advanced Materials Institute Limited. Invention is credited to Ho-Yin Fong, Tik Ho Lau, Jifan Li, Kai Li, Yuyan Song.
Application Number | 20180022888 15/216739 |
Document ID | / |
Family ID | 60988227 |
Filed Date | 2018-01-25 |
United States Patent
Application |
20180022888 |
Kind Code |
A1 |
Li; Jifan ; et al. |
January 25, 2018 |
RECYCLING PROCESS FOR EXPANDED POLYSTYRENE WASTES
Abstract
Disclosed is an environmentally friendly recycling process for
expanded polystyrene (EPS) wastes using dissolution process and
supercritical CO.sub.2 extraction process. The recycling process
may enable condensing an expanded polystyrene (EPS) by dissolving
the EPS into a solvent and one or more additives thereby obtaining
an expanded polystyrene (EPS) solution. The recycling process may
further enable purifying the EPS solution using at least one of a
filtration process and a separation process in order to obtain a
purified expanded polystyrene (EPS) solution. Further, the
recycling process may further enable extracting the polystyrene
from the solvent in the purified expanded polystyrene (EPS)
solution using a supercritical CO.sub.2 extraction method in order
to obtain a recycled polystyrene. The recycling process enables in
significant reduction of the volume of EPS thereby saving the
logistical cost as well as facilitating increase in quantity,
quality and purity of the recycled polystyrene.
Inventors: |
Li; Jifan; (Hong Kong,
HK) ; Lau; Tik Ho; (Hong Kong, HK) ; Fong;
Ho-Yin; (Hong Kong, HK) ; Song; Yuyan; (Hong
Kong, HK) ; Li; Kai; (Hong Kong, HK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nano and Advanced Materials Institute Limited |
Hong Kong |
|
HK |
|
|
Family ID: |
60988227 |
Appl. No.: |
15/216739 |
Filed: |
July 22, 2016 |
Current U.S.
Class: |
521/46 |
Current CPC
Class: |
Y02P 20/54 20151101;
C08J 11/08 20130101; Y02W 30/701 20150501; Y02W 30/62 20150501;
C08J 2325/06 20130101; Y02P 20/544 20151101 |
International
Class: |
C08J 11/08 20060101
C08J011/08 |
Claims
1. A process for recycling an expanded polystyrene (EPS),
comprising: condensing an expanded polystyrene (EPS) by dissolving
the EPS into a solvent thereby obtaining an expanded polystyrene
(EPS) solution; purifying the EPS solution using at least one of a
filtration process and a separation process in order to obtain a
purified expanded polystyrene (EPS) solution; and extracting the
solvent from the purified expanded polystyrene (EPS) solution using
supercritical CO.sub.2 in order to obtain a recycled
polystyrene.
2. The process of claim 1, wherein the solvent is a green organic
solvent comprising at least one of limonene, dipentene, cymene,
anisole, cinnamaldehyde, phellandrene, linalool, pinene, terpinene
and terpineol.
3. The process of claim 1, wherein one or more additives is added
into the solvent for dissolving the EPS.
4. The process of claim 3, wherein the one or more additives are
selected from a group comprising ethanol, methanol, isopropyl
alcohol, pentane, hexane and a mixture thereof.
5. The process of claim 4, wherein the one or more additives
comprise ethanol.
6. The process of claim 4, wherein the volume ratio of the solvent
to ethanol is 85:15.
7. The process of claim 4, wherein the volume ratio of the solvent
to ethanol is 80:20.
8. The process of claim 3, wherein the volume concentration of the
one or more additives is in a range of 1% to 50% and preferably 1%
to 25%.
9. The process of claim 1, wherein the condensation process is
operated at a temperature within a range of 20.degree. C. to
80.degree. C.
10. The process of claim 3, wherein the one or more additives
accelerates the dissolving process of the EPS.
11. The process of claim 1, wherein the purification of the EPS
solution using the filtration process enables removing solid
contaminants and/or liquid contaminants from the EPS solution.
12. The process of claim 1, wherein the purification of the EPS
solution using the separation process enables removing liquid
contaminants from the EPS solution.
13. The process of claim 1, wherein the supercritical CO.sub.2
extraction method enabling the extraction of the solvent from the
polystyrene solution is operated at a predefined temperature, a
predefined pressure and a predefined gas flow.
14. The process of claim 13, wherein the predefined temperature is
within a range of 40.degree. C. to 80.degree. C.
15. The process of claim 13, wherein the predefined pressure is
within a range of 5 MPa to 50 MPa.
16. The process of claim 13, wherein the predefined gas flow is
within a range of 1 L/h to 50 L/h.
17. The process of claim 1 further comprising obtaining a recycled
solvent in addition to the recycled polystyrene, wherein the
recycled solvent is further utilized as the solvent in the
condensation of EPS.
Description
TECHNICAL FIELD
[0001] The present application in general relates to a process of
recycling expanded polystyrene (EPS) wastes, and more particularly
to an environmentally friendly and cost effective recycling process
for EPS wastes using a dissolution process and supercritical
CO.sub.2 extraction process.
BACKGROUND
[0002] Expanded polystyrene (EPS) is a rigid, tough, and
closed-cell foam, which has multiple applications related to
insulation and packing. EPS may be recycled to obtain recycled
polystyrene. The existing recycling process faces many challenges.
In the recycling process, usually the EPS wastes are transported
from sources to factory sites where the EPS wastes are processed to
obtain the desired recycled polystyrene. However, it has been
observed that the cost required for the transport of the EPS wastes
is extremely high. This is because, the EPS wastes have low density
and large volume thereby tending to occupy huge spaces but with
actual low contents. In an example, an EPS block (in
100.times.100.times.100 cm) with volume 1,000,000 cm.sup.3 weighs
around 16 kg only. Therefore, the high transportation cost is a big
hurdle to recycle EPS wastes.
[0003] Another technical challenge observed in the conventional
recycling process is the condensation speed required for converting
solid EPS wastes into dissolved form in solvent like limonene and
cymene. The rate of the existing recycling process is not
satisfying the needs of modern days when the solvent is used
solely.
[0004] Existing practice in treating expanded polystyrene waste is
by hot melting or incineration, which is not friendly to the
environment and poor in efficiency as revealed by low extraction
yield, high electricity demand and unavoidable toxins emission
during the process.
SUMMARY
[0005] Before the present process and its steps are described, it
is to be understood that this application is not limited to the
particular process and its steps as described, as there can be
multiple possible embodiments which are not expressly illustrated
in the present application. It is also to be understood that the
terminology used in the description is for the purpose of
describing the particular versions or embodiments only, and is not
intended to limit the scope of the present application. This
summary is not intended to identify essential features of the
claimed subject matter nor is it intended for use in detecting or
limiting the scope of the claimed subject matter.
[0006] A process for recycling an expanded polystyrene (EPS),
including three distinct processes is disclosed. The process may
include condensing an expanded polystyrene (EPS) by dissolving the
EPS into a solvent and optionally with one or more additives
thereby obtaining an expanded polystyrene (EPS) solution. The
process may further include purifying the EPS solution using at
least one of a filtration process and a separation process in order
to obtain a purified expanded polystyrene (EPS) solution. Further,
the process may include extracting the solvent from the purified
expanded polystyrene (EPS) solution using a supercritical CO.sub.2
in order to obtain recycled polystyrene.
[0007] In some embodiments, the solvent may be a green organic
solvent including at least one of limonene, dipentene, cymene,
anisole, cinnamaldehyde, phellandrene, linalool, pinene, terpinene
and terpineol.
[0008] The one or more additives accelerate the dissolving process
of the EPS. In some embodiments, the one or more additives may be
selected from a group comprising ethanol, methanol, isopropyl
alcohol, pentane, hexane and a mixture thereof. The one or more
additives may be ethanol. In some embodiments, the volume ratio of
the solvent to ethanol may be in the range of about 85:15 to about
80:20. The volume concentration of the one or more additives may be
in a range of about 1% to about 50% and preferably about 1% to
about 25%.
[0009] In some embodiments, the condensation process may be
operated at a temperature within a range of about 20.degree. C. to
about 80.degree. C.
[0010] The purification of the EPS solution using the filtration
process enables removing solid contaminants and/or liquid
contaminants from the EPS solution and the separation process
enables removing liquid contaminants from the EPS solution.
[0011] In accordance with aspect of the present application, the
supercritical CO.sub.2 extraction method enabling the extraction of
the EPS from the solvent is operated at a predefined temperature, a
predefined pressure and a predefined gas flow. In some embodiments,
the predefined temperature may be within a range of about
40.degree. C. to about 80.degree. C. The predefined pressure may be
within a range of about 5 MPa to about 50 MPa. The predefined gas
flow may be within a range of about 1 L/h to about 50 L/h.
Moreover, the supercritical CO.sub.2 extraction method further
enables obtaining a recycled solvent in addition to the recycled
polystyrene based upon the extraction of the EPS from the solvent
in the EPS solution. The recycled solvent obtained may be further
utilized as the solvent in the condensation of EPS.
[0012] These and other features, aspects, and advantages of the
present application will become better understood with reference to
the following description and appended claims.
BRIEF DESCRIPTION OF DRAWINGS
[0013] The detailed description is described with reference to the
accompanying Figures. In the Figures, the left-most digit(s) of a
reference number identifies the Figure in which the reference
number first appears. The same numbers are used throughout the
drawings to refer like features and components.
[0014] FIG. 1 illustrates a flow diagram depicting steps of
recycling process for EPS, in accordance with an embodiment of the
present application.
[0015] FIG. 2 illustrates a filtration process employed for removal
of dirt (solid contaminants), in accordance with an embodiment of
the present application.
[0016] FIG. 3 illustrates a filtration process employed for removal
of liquid contaminants in the EPS solution, in accordance with an
embodiment of the present application.
[0017] FIG. 4 illustrates an extracted polystyrene using
supercritical CO.sub.2, in accordance with an embodiment of the
present application.
DETAILED DESCRIPTION
[0018] Some embodiments of this patent application, illustrating
all its features, will now be discussed in detail.
[0019] Reference throughout the specification to "various
embodiments," "some embodiments," "one embodiment," or "an
embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment. Thus, appearances of the
phrases "in various embodiments," "in some embodiments," "in one
embodiment," or "in an embodiment" in places throughout the
specification are not necessarily all referring to the same
embodiment. Furthermore, the particular features, structures or
characteristics may be combined in any suitable manner in one or
more embodiments.
[0020] The words "comprising," "having," "containing," and
"including," and other forms thereof, are intended to be equivalent
in meaning and be open ended in that an item or items following any
one of these words is not meant to be an exhaustive listing of such
item or items, or meant to be limited to only the listed item or
items.
[0021] It must also be noted that as used herein and in the
appended claims, the singular forms "a," "an," and "the" include
plural references unless the context clearly dictates otherwise.
Although any systems and methods similar or equivalent to those
described herein can be used in the practice or testing of
embodiments of the present application, the preferred, systems and
methods are now described. The disclosed embodiments are merely
exemplary of the present application, which may be embodied in
various forms.
[0022] The present application discloses an environmentally
friendly recycling process of expanded polystyrene waste, which
solves the volume problem of polystyrene foamed materials and
allows easy and inexpensive shipment of the polystyrene foamed
materials after reduction of the volume. The recycling process
produces a high quality, pure recycled polystyrene using
supercritical CO.sub.2 extraction method under specified
temperature and pressure. The detailed description of the recycling
process is further explained referring to FIGS. 1-4 below.
[0023] FIG. 1 is a flow diagram illustration steps of recycling
process for EPS, in accordance with an embodiment of the present
application. As shown, the recycling process for expanded
polystyrene (EPS) wastes involves three steps including a
condensing step using dissolution process, a purification step
using at least one of filtration process and separation process,
and an extraction step using supercritical CO.sub.2.
[0024] Referring to FIG. 1, the condensing step using dissolution
process includes dissolving the EPS waste 10 in a suitable solvent
11 capable of significantly dissolving EPS and forming an
EPS-solvent solution 12 (also referred hereinafter as polystyrene
solution) as shown in FIG. 1, thereby reducing the volume of EPS
waste. In various embodiments, the suitable solvent may be a green
organic solvent including at least one of limonene, dipentene,
cymene, anisole, cinnamaldehyde, phellandrene, linalool, pinene,
terpinene and terpineol. In one exemplary embodiment, the EPS waste
10 (shown in FIG. 1) is dissolved into limonene. It must be
understood that limonene, being a natural solvent, may dissolve the
EPS 10 easily so as to reduce the volume of the EPS 10 to less than
1/20 of original volume of the EPS waste 10. Therefore, the
resultant EPS-solvent 12 (shown in FIG. 1) has a volume reduction
of more than 20 times from the original size of the EPS waste
10.
[0025] It is to be noted that the dissolving rate in the
aforementioned dissolution process may be further enhanced by
dissolving the EPS waste 10 in the solvent 11 along with one or
more additives. In some embodiments, the volume concentration of
the one or more additives is in a range of about 1% to about 50%,
and preferably about 1% to about 25%. In various embodiments, the
one or more additives may be selected from a group consisting of
ethanol, methanol, isopropyl alcohol (IPA), pentane, hexane and a
mixture thereof. In one exemplary embodiment, the EPS waste 10
(shown in FIG. 1) is dissolved into ethanol along with limonene. It
must be understood that with the addition of the additives like
ethanol, the dissolving rate of the dissolution process is
increased more than 100%, whereas the dissolution time is reduced
by more than two times. The additives like ethanol further
decreases the viscosity of the limonene solution and thereby leads
to improve penetration of limonene solution into the expanded
polystyrene (EPS).
[0026] It must be understood that the solvent 11 (e.g. limonene)
before the dissolution process is originally transparent, clear and
has lemon odor. After the condensation is completed, the EPS
solution obtained is cloudy, viscous and has lemon odor. It is
observed that by selecting the right solvents and additives, the
volume of EPS waste may be significantly reduced and the dissolving
time may be greatly shortened. The significant reduction in the
volume of EPS further assists in reduction of the transportation
cost. It is to be noted that the aforementioned dissolution process
may be carried out under room temperature and pressure. Further,
the dissolution process may be completed within about 2-3 hours to
yield the EPS-solvent solution 12 with 40% of its weight extracted
from EPS waste 10. In one embodiment, the condensation process is
operated at a temperature within a range of about 20.degree. C. to
about 80.degree. C.
[0027] Referring to FIG. 1, after the condensation step, the next
step is the purification step involving at least one of the
filtration process and the separation process for removing the
contaminants from the polystyrene solution (i.e. EPS-solvent
solution 12 shown in FIG. 1). In an embodiment, the filtration
process may be employed in order to remove the solid contaminants
(solid particles) from the polystyrene solution. Further, the
separation process and/or filtration process may be employed in
order to remove the liquid contaminants (liquid particles) from the
polystyrene solution.
[0028] It is to be understood that the EPS waste 10 may be
contaminated with dirt and liquids thereby affecting the quality of
the recycled polystyrene. In case the EPS waste 10 collected is
dirty, the resultant solution (i.e. EPS-solvent solution 12 shown
in FIG. 1) containing the EPS waste 10 dissolved in the solvent 11
is full of contaminants. Such contaminants may not be extracted
during the extraction step using supercritical CO.sub.2 (explained
in detail in subsequent paragraphs). The contaminants therefore may
be present in the polystyrene obtained as outcome of the extraction
step thereby reducing purity of the polystyrene. Thus, the
purification step is performed on the polystyrene solution 12 by
means of at least one of the filtration process and the separation
process.
[0029] Referring to FIG. 2, the purification of the polystyrene
solution 12 using the filtration process is shown, in accordance
with an embodiment of the present application. As shown in FIG. 2,
the filtration process is carried out using an appropriate filter
21 (e.g. 500 mesh sieve) capable of removing the solid contaminants
from the polystyrene solution 12. Referring to FIG. 3, the
purification of the polystyrene solution using the filtration
process is shown, in accordance with an embodiment of the present
application. As shown in FIG. 3, the filtration process is carried
out using a filter 31 (e.g. 500 mesh sieve) to remove the liquid
contaminants. Based on the purification of the polystyrene solution
12 using at least one of the filtration process and the separation
process, a purified polystyrene solution or treated polystyrene
solution (indicated as filtered solution 13 in FIG. 1) is obtained.
The filtered solution may include no or little amount of
contaminates which may have negligible effect on the quality of the
final recycled polystyrene obtained as result of the extraction
step explained in detail as below.
[0030] Referring to FIG. 1, after the purification step, the next
step is the extraction step using supercritical CO.sub.2 for
separation of the polystyrene from the solvent in the filtered
solution 13. In the extraction step, the filtered solution 13 is
placed for supercritical CO.sub.2 extraction for about 1-3 hours
depending on the amount of dissolved polystyrene in the solution.
Under specified temperature and pressure, CO.sub.2 is in
supercritical form, which can dissolve and carry away the solvent
from the filtered polystyrene solution 13. The recycled solvent 14
may be reused for the condensation of EPS. In one embodiment, the
extracted polystyrene is the polystyrene shown in FIG. 4.
[0031] It must be understood that the supercritical CO.sub.2
extraction process is used to extract the solvent from the
polystyrene solution. The equilibrium and solubility of the
supercritical CO.sub.2, solvent and polystyrene components in the
ternary system are important factors in controlling the efficiency
of the extraction process. Due to the low solubility of the
polystyrene and high solubility of the solvent in supercritical
CO.sub.2, the supercritical CO.sub.2 is used as an anti-solvent to
separate solvent from the solution so as to make the extraction
feasible. It is to be noted that pressure and temperature are both
important parameters for the extraction process, which affect
solubility of the solvent so as to affect the quality of the
recycled polystyrene.
[0032] Generally, higher pressure leads to increased solubility;
solubility is also likely to rise with increasing temperature (e.g.
.about.60.degree. C.) when the pressure is higher than a critical
point. The efficiency of the extraction process is also governed by
flow rate of supercritical CO.sub.2, as the density of CO.sub.2
changes along with varying temperatures. A high flow rate of
supercritical CO.sub.2 may ensure that the extraction is completely
limited by diffusion but is inevitably wasteful of solvent.
Therefore, efficiency of the extraction system is a delicate
balance between maximizing the flow rate while minimizing the
amount of solvent needed to be spent. For instance, at 60.degree.
C. and 150 bar, it takes approximately one hour to complete the
extraction of polystyrene from solution. The extraction process can
be speeded up by increasing the pressure, which leads to the
increased solubility of the solvent in supercritical CO.sub.2.
[0033] Based on the supercritical CO.sub.2 extraction process, a
high quality and pure polystyrene 41 (as shown in FIG. 4) may be
obtained under predefined temperature, predefined pressure and
predefined gas flow. In one embodiment, the predefined temperature
is within a range of about 40.degree. C. to about 80.degree. C. In
one embodiment, the predefined pressure is within a range of about
5 MPa to about 50 MPa. In one embodiment, the predefined gas flow
is within a range of about 1 L/h to about 50 L/h. The extracted
polystyrene 41 (shown in FIG. 4) has a higher molecular weight and
a lower polymeric distribution index (PDI) as compared to the
original EPS 10 shown in FIG. 1.
[0034] In accordance with an embodiment of the present application,
the aforementioned recycling process is further described by
referring to various examples as below.
Example 1
[0035] The limonene as a solvent may dissolve large amount of EPS
so as to reduce its volume. For instance, referring to Table 1
below, it is observed that the volume of 206 g EPS is around 12360
ml which may be reduced to 600 ml solvent solution 12 after
dissolving in 500 ml of limonene i.e. organic solvent 11.
TABLE-US-00001 TABLE 1 Volume of limonene 500 mL Total weight of
EPS dissolved 206 g Percentage of EPS dissolved in 500 ml limonene
41.2 wt % (~0.4 g/mL) Final volume of Limonene solution 600 mL
[0036] In another embodiment, cymene may be used as an alternative
solvent to Limonene. It is to be noted that -cymene has similar
properties and capability as that of limonene. Table 2 below
illustrates the performance of cymene in comparison to that of the
limonene.
TABLE-US-00002 TABLE 2 Solvent (20 mL) Mass of EPS/g Dimension Time
needed/s Limonene 0.117 1.8 .times. 1.8 .times. 1.8 cm 68.7
Limonene 0.495 4.4 .times. 3.8 .times. 1.9 cm 63.25 cymene 0.114
1.8 .times. 1.8 .times. 1.8 cm 40.35 cymene 0.495 4.4 .times. 3.8
.times. 1.9 cm 32.35
Example 2
[0037] Some chemicals as the additives to the solvent could
accelerate the dissolving process. As shown in the Table 3, when
the additives are added to the solvent, the dissolving time may be
significantly shortened.
TABLE-US-00003 TABLE 3 Weight of EPS Block .apprxeq. 0.5 g Size of
EPS block: Volume of 4.4 .times. 3.8 .times. 1.9 cm Limonene = 20
ml Volume concentration of additives Additives 0% 1% 2% 3% 4%
Ethanol 40 s 37 s 37 s 37 s 34 s Methanol 40 s 32 s 31 s 31 s 28 s
Pentane 40 s 46 s 28 s 28 s 29 s Hexane 40 s 38 s 39 s 33 s 34
s
[0038] For high concentration of EPS solution, ethanol as the
additive is more effective on reducing the dissolving time. To
balance the efficiency and the damage to the environment, ethanol
is considered as the best choice among others. As observed from
Table 4 below, with the presence of 20% of ethanol in the solvent,
the dissolving time is reduced by more than 3 times.
TABLE-US-00004 TABLE 4 Limonene content Ethanol content Time % Time
(vol %) (vol %) required/sec difference 100 0 569 0% 85 15 280 -51%
80 20 164 -71%
[0039] To compromise with the efficiency and the demand of
chemicals, the solvent: ethanol ratio=85:15 is considered as the
most effective option which saves 50% of time needed.
Example 3
[0040] It is necessary to remove the contaminants like dirt and
other liquid from polystyrene solution before supercritical
CO.sub.2 extraction process for obtaining the high quality of
recycled polystyrene. Filtration process is employed to remove
those contaminants and purify the polystyrene solution. To remove
the dirt from polystyrene solution by filtration, as shown in FIG.
2, a 500 mesh filter 21 is able to separate solid impurities and
liquid impurities from the solution. To remove the liquid
contaminations (like chili sauce and soy sauce) from polystyrene
solution, it is well enough to use a filter with 500 mesh size.
Example 4
[0041] The high quality of recycled polystyrene may be obtained
from the polystyrene solution through supercritical CO.sub.2
extraction process. While CO.sub.2 is under certain temperature and
pressure, it is in supercritical form, which may dissolve and carry
away the solvent from the polystyrene solution. Thus, dry and pure
polystyrene is left as the final recycled product (recycled
polystyrene).
[0042] In addition to dry and pure polystyrene, as shown in FIG. 1,
recycled solvent 14 is also obtained from the extraction process
which can be reused for the condensation process.
TABLE-US-00005 TABLE 5 Experimental conditions Sample Pressure
Temperature Time Volume Name (MPa) (.degree. C.) (min) (mL) M.sub.n
M.sub.w PDI Remark Sample A 20 50 60 230 130,694 212,461 1.626
Extracted PS Sample B 25 55 50 200 132,599 212,382 1.602 Extracted
PS Sample C 25 60 60 150 105,078 205,448 1.955 Extracted PS Sample
D 15 50 45 50 101,286 203,527 2.009 Extracted PS Sample E 10 50 60
60 94,768 202,208 2.134 Extracted PS Sample F 15 50 60 50 115,064
208,003 1.808 Extracted PS Original -- -- -- -- 78,142 194,509
2.489 Virgin PS polystyrene
[0043] The GPC results illustrated in Table 5 depicts that the
extracted polystyrene has higher molecular weight and lower PDI as
compared to the original polystyrene. Thus, the extraction process
helps to remove the small molecule and impurity from the
polystyrene so as to obtain the high quality of recycled
polystyrene 41 as shown in FIG. 4.
[0044] Exemplary embodiments discussed above may provide certain
advantages. Though not required to practice aspects of the
application, these advantages may include those provided by the
following features.
[0045] Some embodiments enable a recycling process for EPS
facilitating shrinking the size of EPS blocks. According to the
recycling process, with the aid of solvent, the size of EPS blocks
may be shrunken by 20 times of its original volume.
[0046] Some embodiments enable a recycling process for EPS
facilitating reduction in transportation cost due to reduction in
volume and thereby improving the transportation efficiency.
[0047] Some embodiments enable a system and a method for increasing
the speed of condensation process. The increase in the speed and
thereby reduction in the time required for condensation process is
enabled based upon addition additives such as ethanol and IPA which
assists in reducing the time required by 50%. The improvement in
the condensation efficiency saves time and thus saves cost.
[0048] Some embodiments enable a recycling process for EPS
facilitating removal of solid and liquid impurities from the
polystyrene solution so that the final recycled polystyrene is free
from the contaminates and/or impurities.
[0049] Although embodiments for processes and methods of recycling
an expanded polystyrene (EPS) have been described in language
specific to structural features and/or methods, it is to be
understood that the appended claims are not necessarily limited to
the specific features or methods described. Rather, the specific
features and methods are disclosed as examples of embodiments for
recycling an expanded polystyrene (EPS).
* * * * *